CN111344523A

CN111344523A - Intelligent air purification

Info

Publication number: CN111344523A
Application number: CN201880072551.5A
Authority: CN
Inventors: 苏婧; 张志强
Original assignee: Koninklijke Philips NV
Current assignee: Fansongni Holdings Ltd
Priority date: 2017-11-09
Filing date: 2018-11-07
Publication date: 2020-06-26
Anticipated expiration: 2038-11-07
Also published as: CN111344523B; EP3707439B1; WO2019091987A1; EP3707439A1; PL3707439T3

Abstract

An air cleaning monitoring system (10) for monitoring an air cleaning device (50) adapted to clean air in an enclosed space (1) is disclosed. The air purification monitoring system (10) comprises: a processor (31) arranged to: -receiving an indication of a rate of spontaneous ventilation between the enclosed space (1) and the outdoor space; determining the spontaneous ventilation rate from the received indication; and generating control signals for an airflow shifting device (65, 67, 69) of the air cleaning device (50) in dependence on the calculated spontaneous ventilation rate, the control signals causing the airflow shifting device (65, 67, 69) to control the rate of forced ventilation airflow (82) such that the forced ventilation airflow rate exceeds the spontaneous ventilation rate. An air purification apparatus, a method and a computer program product are also disclosed herein.

Description

Intelligent air purification

Technical Field

The present invention relates to an air purification monitoring system for monitoring an air purification device adapted to purify air in an enclosed space.

The invention also relates to an air cleaning device adapted to be controlled by such an air cleaning monitoring system.

The invention also relates to a method for controlling such an air cleaning device.

The invention also relates to a computer program product for implementing such a method on an air cleaning monitoring system.

Background

Air purifiers are common in today's society for cleaning air in confined spaces, such as rooms, for example, to reduce exposure of people in such confined spaces to harmful or unpleasant contaminants, such as allergens, particulates, odors, and the like. To this end, air purifiers typically include one or more pollutant removal structures, such as one or more filtersCatalytic converters, electrostatic precipitators, and the like. The one or more filters may include air filters, such as carbon filters, HEPA filters, odor filters, antimicrobial filters, and the like. Catalytic converters may be used to break down gaseous pollutants into smaller molecules, such as H₂O and CO₂. An electrostatic precipitator may be employed to remove charged particles via the collector plates. Other contaminant removal techniques employed in such purifiers are also known.

One particular class of air purifiers includes a Fresh Air Purification Unit (FAPU), in which fresh air (i.e., outdoor air) is introduced into a confined space after passing through one or more pollutant removal structures to at least partially remove potentially harmful constituents, such as particulate matter, NO, from the fresh air_XOzone, etc., which can lead to health problems (such as respiratory diseases, e.g., asthma) in the case of exposure of patients suffering from respiratory diseases to such substances. However, the filtering capability of such FAPU is limited, which means: when outdoor air is heavily polluted, the remaining pollutants will enter the confined space, which is highly undesirable. In addition, such severe contamination can quickly saturate the contaminant removal structures in such FAPU, making it necessary to periodically replace these contaminant removal structures.

This problem can be solved by using a separate air purifier in the confined space, which air purifier is generally very efficient in particulate matter removal, so that particulate matter entering the confined space from the outside through natural ventilation can be effectively removed. In order to operate such a self-contained air purifier as efficiently as possible, it is suggested to operate such a device in a hermetically sealed space, but this has the following disadvantages: potentially harmful substances generated in the confined space can accumulate. Such substances will also be referred to as undesirable substances, i.e. airborne components which, at least at certain concentrations, are harmful to the person inhaling the substance. For example, the indoor CO should be kept₂The concentration remains below a certain threshold due to the elevated CO₂The concentration will result in exposure to such elevated concentrationsPeople feel drowsiness and headache. Other examples of such undesirable substances include Volatile Organic Compounds (VOCs), such as formaldehyde and toluene, which may be present at elevated levels after decoration of confined spaces and which may harm the health of people exposed to such compounds.

Another way of preventing contaminated outdoor air (e.g. car exhaust) from entering such enclosed spaces is provided in KR 2008/104744, KR 2008/104744 discloses a system for purifying indoor air by sensing indoor and outdoor pressures to ensure that the indoor pressure is higher than the outdoor pressure. While this intelligent or smart air ventilation system is better equipped to prevent highly contaminated outdoor air from entering confined spaces, it does not guarantee that the system operates at optimum efficiency.

Disclosure of Invention

The present invention seeks to provide an air cleaning monitoring system for monitoring an air cleaning device which ensures that the air cleaning device is operated with improved efficiency when cleaning air within an enclosed space.

The present invention also seeks to provide an air cleaning device which can be controlled using such an air cleaning monitoring system.

The present invention further seeks to provide a computer-implemented method of controlling such an air cleaning apparatus.

The present invention also seeks to provide a computer program product that may be used to configure an air purification monitoring system to implement the computer-implemented method.

According to one aspect, there is provided an air purification monitoring system for monitoring an air purification device adapted to purify air in an enclosed space, the air purification device comprising: a first inlet for receiving outdoor air from the outdoor space; and at least one outlet coupled to the first inlet; a filter device positioned between the first inlet and the at least one outlet; and an airflow displacement device arranged to generate a forced draft airflow from the first inlet to the at least one outlet; this air purification monitoring system includes: a processor arranged to: receiving an indication of a spontaneous ventilation rate (ventilationrate) between the enclosed space and the outdoor space; determining a spontaneous ventilation rate from the received indication; and generating a control signal for the airflow shifting means in dependence on the calculated spontaneous ventilation rate, the control signal causing the airflow shifting means to control the rate of forced ventilation airflow such that the forced ventilation airflow rate exceeds the spontaneous ventilation rate.

The invention is based on the following insight: when the air cleaning apparatus forces an airflow into the enclosed space at a rate that exceeds the spontaneous ventilation rate between the enclosed space and the exterior by a defined amount (e.g., a small amount), an optimal mode of operation of the air cleaning apparatus is achieved in terms of efficiency such that a positive pressure is generated within the enclosed space that prevents undesirable substances (such as particulate matter or other contaminants) from the exterior from entering the enclosed space, while the amount of energy required by the air cleaning apparatus to generate such a positive pressure is minimized. This is achieved by obtaining an estimate of the spontaneous ventilation rate, based on which the air cleaning device is operated.

In an embodiment, the processor is arranged to determine the spontaneous ventilation rate based on the indication and the volume of the enclosed space to obtain an accurate estimate of the spontaneous ventilation rate.

The indication may comprise a series of sensor readings over time of the concentration of the analyte of interest within the enclosed space, and wherein the processor is arranged to calculate the spontaneous ventilation rate from the series of sensor readings. For example, in a scenario where the rate of production of the analyte of interest is known, the spontaneous ventilation rate of the enclosed space may be obtained from such a series of sensor readings. To this end, the air purification monitoring system may further include: an analyte sensor arranged to provide the series of sensor readings. Alternatively, the sensor readings may be provided by an analyte sensor external to the air purification monitoring system.

In another embodiment, the indication comprises outdoor wind speed information. This example is based on the following insight: there is a direct relationship between the spontaneous ventilation rate of the enclosed space and the outdoor wind speed, so that the spontaneous ventilation rate can be derived from such an indication of the outdoor wind speed.

In a further embodiment, the indication comprises an outdoor air temperature and an indoor air temperature, and wherein the processor is arranged to calculate the spontaneous ventilation rate from a difference between the outdoor air temperature and the indoor air temperature. This example is based on the following insight: there is a direct relationship between the ventilation rate of the enclosed space and the temperature gradient between the outdoor temperature and the indoor temperature (i.e. the temperature within the enclosed space) so that the spontaneous ventilation rate can be derived from the difference between these temperatures. To this end, the air purification monitoring system may further include at least one of: an indoor temperature sensor for determining an indoor air temperature; and an outdoor temperature sensor for determining an outdoor air temperature. Alternatively, such temperature readings may be obtained from alternative sources external to the air purification monitoring system.

The processor may be further arranged to: receiving pressure sensor readings from a pressure sensor indicative of a pressure within an enclosed space; and generating a control signal for the airflow displacement device based on the spontaneous ventilation rate and the pressure sensor reading. Optionally, the air purification monitoring system may include: such a pressure sensor. In this way, a feedback mechanism may be provided in which the pressure readings are used to ensure that the correct amount of positive pressure is generated within the enclosed space, thereby further improving the efficiency of the air cleaning device.

According to another aspect, there is provided an air purification device adapted to purify air in an enclosed space, comprising a first inlet for receiving outdoor air from an outdoor space, and at least one outlet coupled to the first inlet; a filter device positioned between the first inlet and the at least one outlet; and an airflow shifting arrangement arranged to produce a forced draft airflow from the first inlet to the at least one outlet, wherein the airflow shifting arrangement is responsive to a control signal generated with the air purification monitoring system according to any one of the embodiments described herein. Such air cleaning apparatus benefits from being operable in an efficient manner to generate a positive pressure within the enclosed space for preventing unwanted substances from entering the enclosed space from outside the room, as explained previously.

In at least some embodiments, the air purification apparatus further comprises: the air purification monitoring system according to any one of the embodiments described herein, thereby providing a self-contained air purification device comprising the inventive air purification monitoring system.

The air cleaning apparatus further comprises a second inlet for receiving indoor air from the enclosed space connected to the at least one outlet, wherein the filter device is positioned between the first and second inlets and the at least one outlet; and the gas flow shifting means is further arranged to generate a recirculating gas flow from the second inlet to the at least one outlet. This has the following advantages: the indoor air may also be purified by an air purification device, for example to reduce the concentration of undesirable substances such as volatile organic compounds. Additional embodiments may include an air purification apparatus, further comprising: an exhaust mode in which the indoor air is discharged to the outside, for example, when the indoor air includes a high concentration of an undesirable substance (e.g., CO) that cannot be removed by the filter device₂) This may be advantageous, in which case such contaminated air may be removed from the enclosed space.

According to yet another aspect, there is provided a computer-implemented method for generating a control signal for controlling an air purification apparatus according to any of the embodiments described herein, the method comprising: receiving an indication of a rate of spontaneous ventilation between the enclosed space and the outdoor space; determining a spontaneous ventilation rate from the received indication; and generating a control signal for the airflow shifting means in dependence on the calculated spontaneous ventilation rate, the control signal causing the airflow shifting means to control the rate of forced ventilation airflow such that the forced ventilation airflow rate exceeds the spontaneous ventilation rate. Generating such a control signal facilitates control of the air cleaning device such that the air cleaning device operates in an efficient manner while establishing a positive pressure within the enclosed space as explained previously.

Preferably, determining the spontaneous ventilation rate from the received indication comprises: the spontaneous ventilation rate is determined based on the indication and the volume of the enclosed space to obtain a particularly accurate estimate of the spontaneous ventilation rate.

According to yet another aspect, there is provided a computer program product comprising a computer readable storage medium containing computer readable program instructions for causing a processor to carry out a method according to any of the embodiments described herein, when executed on the processor of an air purification monitoring system according to any of the embodiments described herein. Such a computer program product may be used to reconfigure an existing air purification monitoring system, which may be more cost-effective than replacing such a system to implement functionality according to embodiments of the present invention.

Drawings

Embodiments of the invention are described in more detail and by way of non-limiting examples with reference to the accompanying drawings, in which:

fig. 1 schematically depicts an air purification apparatus comprising an air purification monitoring system according to an embodiment;

FIG. 2 schematically depicts an air purification apparatus including an air purification monitoring system according to another embodiment;

FIG. 3 schematically depicts an air purification apparatus according to an example embodiment;

FIG. 4 schematically depicts an air purification apparatus according to another example embodiment;

FIG. 5 schematically depicts an air purification apparatus according to yet another example embodiment;

FIG. 6 schematically depicts an air purification apparatus according to yet another example embodiment;

FIG. 7 is a flow chart of a method of controlling an air purification apparatus located in a space filled with air according to an embodiment;

FIG. 8 shows a graph depicting outdoor wind speed (x-axis, m/s) versus spontaneous ventilation rate (y-axis, h)^-1) Graph of the relationship between.

Fig. 9 shows a set of graphs associated with a first ventilation condition of a room in which an air cleaning device according to an embodiment of the invention is placed;

FIG. 10 shows a set of graphs associated with a second ventilation condition of a room in which an air purification apparatus according to an embodiment of the present invention is placed; and

FIG. 11 is a graph depicting outdoor and indoor temperature gradients (x-axis, deg.C) versus spontaneous ventilation rate (y-axis, h)^-1) Graph of the relationship between.

Detailed Description

It should be understood that the figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to indicate the same or similar parts.

Fig. 1 schematically depicts an air purification monitoring system 10 according to an embodiment. The air purification monitoring system 10 is adapted to control the operation of an air purification apparatus 50 installed in an enclosed space 1 (a room such as a house, an office building, etc.). As will be explained in more detail below, the air cleaning device 50 is operable at least in a first mode in which outdoor air is ventilated into the enclosed space 1. In this mode, such forced ventilation is performed at a rate exceeding the rate of natural or spontaneous ventilation between the enclosed space 1 and the outside, for example due to the presence of defects in the airtight seal of the enclosed space 1, which may include an open window or door. This will be explained in more detail below. In some embodiments, the air purification apparatus 50 may also be operated in a second mode in which indoor air within the enclosed space 1 is circulated by the air purification apparatus 50. This air flow is typically passed through one or more pollutant removal structures mounted within the air cleaning device 50 to clean the air before it is discharged into the enclosed space 1. Such air cleaning apparatus 50 may be installed in any suitable manner within the enclosed space 1, such as through an exterior wall, roof or window of a building or dwelling that includes the space 1, such that the air cleaning apparatus 50 may contact an outdoor space from which outdoor air originates. Such air purification devices 50 may include any suitable type of contaminant removal structure (e.g., filters, such as HEPA filters, carbon filters, etc.) to remove contaminants, such as particulate matter, pollen, odors, bacteria, Volatile Organic Compounds (VOCs), such as formaldehyde and toluene, and the like.

The air purification monitoring system 10 generally includes a computing device 30, the computing device 30 including a processor 31. Computing device 30 may be any suitable computing device, such as a personal computer (e.g., desktop or laptop computer, tablet computer), personal digital assistant, mobile communication device (such as a smartphone, etc.). The computing device 30 may form an assembly with the air purifier 50. In such components, the computing device 30 may be a discrete entity or may form part of the air purifier 50, i.e., the air purifier 50 may include the processor 31. The processor 31 may be any suitable processor, such as a general purpose processor or a special purpose processor. Computing device 30 may also include a data storage device 33 communicatively coupled to processor 31.

The computing device 30 is arranged to communicate with one or

more sensors

21, 22, 23. Such sensors may include a pressure sensor 23, a temperature sensor 22, and/or one or more adverse substance sensors 21 (e.g., analyte sensors) for sensing the level of an adverse substance or analyte of interest in the atmosphere within the enclosed space 1 in which the air purification apparatus 50 is located. Typically, the first adverse substance sensor 21 is arranged to sense a concentration or level of an adverse substance, for which purpose the air purification apparatus 50 comprises a pollutant removal structure, such as an air filter or the like arranged to remove the adverse substance. For example, the sensor 21 may be a particulate matter sensor (such as a PM2.5 sensor), a formaldehyde sensor, a toluene sensor, or the like for detecting particulate matter (e.g., PM2.5 or PM10, dust particles, allergens, or the like) having a specific diameter in the atmosphere. Alternatively, the first adverse substance sensor 21 is for monitoring CO within the enclosed space 1₂Horizontal carbon dioxide sensor (CO)₂). In this scenario, as the skilled person will appreciate, the air purification device 50 may not comprise a device capable of removing CO₂The contaminant removal structure of (1).

In a particular embodiment, the processor 31 is also communicatively coupled to an outdoor temperature sensor 24 arranged to sense outdoor temperature. Such an outdoor temperature sensor 24 may be located at any suitable outdoor location, such as, for example, on the exterior surface of a dwelling that includes the enclosed space 1. Alternatively, the processor 31 may be arranged to obtain the outdoor temperature information from an external source, such as a weather service or the like, providing real-time temperature information about the geographical location of the dwelling, over a network connection, such as the internet. However, as will be explained in more detail below, providing the indoor and outdoor temperature information to the processor 31 is not essential to the present invention, such that in alternative embodiments, the indoor temperature sensor 23 and/or the outdoor temperature sensor 24 (or the temperature providing service) may be omitted. In yet another embodiment, the external sensor 24 may be an anemometer for measuring outdoor wind speed as will be explained in more detail below.

The

sensors

21, 22, 23 may be integrated in any suitable device, such as the air purification apparatus 50, the computing device 30, or a separate sensor device 20 (e.g., a sensor cartridge, etc.). Standalone sensor devices (e.g., sensor cartridges) are increasingly available for home use and may include sensors for measuring air pollutants such as Volatile Organic Compounds (VOCs) including formaldehyde and toluene, particles including PM2.5, and environmental parameters such as relative humidity and temperature. The processor 31 may be adapted to monitor the concentration of a specific contaminant, the temperature within the enclosed space 1 and/or the pressure within the enclosed space 1 based on sensor data provided by the

sensors

21, 22, 23 of the sensor device 20. In an embodiment, the processor 31 may be integrated into such a separate sensor device 20, i.e. the separate sensor device 20 may comprise the computing device 30.

The

sensors

21, 22, 23 are communicatively coupled to the computing device 30 by a communication link 25 so that the processor 31 can receive sensor readings from such sensors. Such a communication link may be a wired communication link, for example in case the

sensors

21, 22, 23 are integrated into the computing device 30, or may be a wireless communication link, for example in case the

sensors

21, 22, 23 are located in a different device than the computing device 30, for example in a separate sensor device 20. To this end, the respective devices communicatively coupled by such wireless communication links may include wireless transceivers (not shown). The devices may communicate with each other through their respective wireless transceivers using any suitable wireless communication protocol, such as bluetooth, Wi-Fi, a mobile communication protocol, such as 2G, 3G, 4G, or 5G, a suitable Near Field Communication (NFC) protocol, or a proprietary protocol. In the case of such wireless communication, the respective devices may communicate directly with each other, or may communicate with each other through intermediate devices (such as wireless bridges, routers, hubs, etc.). Any suitable embodiment of wired or wireless communication between such respective devices is envisaged.

The processor 31 may also be communicatively coupled to a data storage device 33, where the data storage device 33 is shown as forming part of the computing device 30. Such a data storage device may be any suitable device for storing digital data, such as random access memory, cache memory, flash memory, solid state storage devices, magnetic storage devices (such as hard disks), optical storage devices, and the like. Alternatively, the data storage device 33 may be separate from the computing device 30, for example a network storage device or cloud storage device accessible to the processor 31 over a network (such as a LAN or the internet). The processor 31 may store sensor data received from one or more of the

connected sensors

21, 22, 23 in a data storage device to collect and store, for example, historical data regarding the level of adverse substances of interest in the atmosphere within the enclosed space 1, including the air purification apparatus 50 from which the processor 31 may derive certain parameters relating to the enclosed space 1 as will be explained in more detail below.

In fig. 1, computing device 30 also includes a sensory output device 35 under the control of processor 31. The sensory output device may be any device capable of producing an output that can be detected by one sense of a human being. For example, sensory output device 35 may be adapted to produce a visual or audible output. For example, sensory output device 35 may include a display and/or one or more LEDs suitable for providing such output.

As the skilled person will readily appreciate, the processor 31 may be adapted to receive sensor data from a plurality of sensors 21 respectively associated with different adverse substances of interest, wherein the processor 31 is adapted to (simultaneously) monitor the respective concentration levels of the different adverse substances of interest by means of the sensor data received from the plurality of sensors in the sensor device 20.

In the above embodiments, the sensory output device 35 forms part of the computing device 30, e.g., may be an integral part of the computing device 30 or may be attached to the computing device 30, e.g., to a monitor or speaker of the computing device 30. In an alternative arrangement, depicted schematically in fig. 2, the sensory output device 35 may form part of a mobile communication device 40, wherein the computing device 30 is adapted to communicate with the mobile communication device over a wireless communication link 37, for example using any of the wireless communication protocols described above. In this embodiment, the operation of the air purification apparatus 50 can be controlled even when the air purification apparatus 50 is not directly in the vicinity of the computing device 30 (e.g. when in a different room or outside a building comprising the air purification apparatus 50), which is advantageous, for example, to ensure that the enclosed space 1 is adjusted to the desired conditions in anticipation of the arrival of a user of the mobile communication device 40 in the enclosed space 1. Any suitable mobile communication device 40 (e.g., smart phone, tablet computer, personal digital assistant, etc.) may be used for this purpose. As the skilled person will readily appreciate, the mobile communication device 40 may be configured with a software application (e.g. app) to interact with the computing device 30 as described above.

In yet another embodiment, the sensor(s) 21, 22, 23, as well as the processor 31 and sensory output device 35 are integrated in an air purification apparatus 50, thereby forming an integrated air purification apparatus 50 according to an embodiment of the present invention.

Next, some examples of the air cleaning device 50 according to the embodiment of the present invention will be described in more detail. A first example is schematically depicted in fig. 3, fig. 3 depicting an air cleaning device 50 adapted to generate a ventilation air flow 82, the ventilation air flow 82 introducing air from an outdoor space into the enclosed space 1 through a contaminant removal structure 63 in a conduit between an outdoor inlet 57 and an indoor outlet 53 of the air cleaning device 50, thereby reducing the concentration of outdoor adverse substances to be introduced into the enclosed space 1. As is well known per se, the duct may also house a heat exchanger 70, which heat exchanger 70 conditions (e.g. heats or cools) the outdoor air before it is introduced into the enclosed space 1 for climate control. The ventilation air flow 82 may be generated using an air displacement device or apparatus 67 such as a fan, ventilator, ion wind generator, air pump, or the like. A valve arrangement 65 may be present to further regulate the airflow rate of the ventilation airflow 82.

Another example of such an air purification apparatus 50 is schematically depicted in fig. 4, where fig. 4 depicts an air purification apparatus 50 adapted to generate a first air flow 81 (from here on referred to as a recirculation air flow 81), a second air flow (i.e. a ventilation air flow 82) and a third air flow 83 (from here on referred to as an exhaust air flow 83). The recirculation air flow 81 recirculates air from within the enclosed space 1 into the enclosed space 1 through the contaminant removal structure 61 in the conduit between the indoor inlet 55 and the first indoor outlet 53 of the air purification device 50, thereby reducing the concentration of indoor adverse substances and purifying the indoor air. The recirculation air flow 81 may be generated using a first air displacement device or equipment 67 such as a fan, ventilator, ion wind generator, air pump, etc.

The ventilation air flow 82 introduces air from the outdoor space into the enclosed space 1 through another contaminant removal structure 63 in another conduit between the outdoor inlet 57 and the second indoor outlet 51 of the air cleaning device 50, thereby reducing the concentration of outdoor undesirable substances to be introduced into the enclosed space 1. As is well known per se, the further duct may also house a heat exchanger 70, which heat exchanger 70 conditions (e.g. heats or cools) the outdoor air before it is introduced into the enclosed space 1 for climate control. A second air-displacement device or apparatus 69 such as a fan, ventilator, ion wind generator, air pump, etc. may be used to generate ventilation air flow 81.

As will be explained in more detail below, the ventilation air flow 82 may be used to create a positive pressure within the enclosed space 1 relative to the outdoor space, thereby forcing air in the enclosed space 1 to advance, i.e. to ventilate the enclosed space 1, e.g. to reduce the concentration of undesirable substances generated within the enclosed space 1 and/or to prevent unfiltered outdoor air comprising a high concentration of undesirable substances, such as, for example, VOCs, or CO generated by persons within the enclosed space 1, in the case of a newly repaired enclosed space 1, from entering the enclosed space 1 by natural or spontaneous ventilation₂。

By way of non-limiting example only, the exhaust airflow 83 may be used to assist in the forced ventilation of the enclosure 1 by forcibly exhausting indoor air under the control of the second air displacement device or apparatus 69. To this end, a third second air-displacement device or apparatus (not shown) may be used instead. The exhaust airflow 83 may pass through yet another conduit extending between an indoor inlet (such as the second inlet 51) and the outdoor outlet 59. A valve arrangement 65 may be present to switch the operation of the second air-displacement device or apparatus 69 between generating the ventilation air flow 82 and the exhaust air flow 83 as will be readily understood by the skilled person.

As previously mentioned, the

contaminant removal structures

61, 63 within the air purification apparatus 50 may be configured to remove any suitable undesirable substances from indoor or outdoor air, such as, for example, O₃、PM 10、PM 2.5、CO、NO₂SO₂Volatile organic compounds such as formaldehyde or toluene, and the like. Furthermore, it should be understood that according to embodiments of the present invention, the air cleaning device 50 is arranged to generate at least a ventilation air flow 82 and preferably also a recirculation air flow 81, which may be achieved by any suitable configuration of the air cleaning device 50.

For example, fig. 5 schematically depicts another example embodiment of the air purification apparatus 50, wherein the air purification apparatus 50 is configured to generate the recirculation air flow 81 and the ventilation air flow 82 using only separate

air displacement devices

67, 69 as previously explained, while in fig. 6 schematically depicts another example embodiment of the air purification apparatus 50, wherein the recirculation air flow 81 and the ventilation air flow 82 are generated using a single air displacement device 67 communicatively coupled to a valve device 65, which valve device 65 allows the air purification apparatus 50 to switch between the recirculation air flow 81 and the ventilation air flow 82 or a mixture thereof. Fig. 6 further schematically depicts that the recirculated air flow 81 and the ventilation air flow 82 share the same indoor outlet 53 of the air cleaning device 50, and it should be understood that in any embodiment of the air cleaning device 50, these air flows may share such an outlet. Furthermore, it should be understood that further configuration variations of the air cleaning device 50 are of course possible without departing from the teachings of the present invention, such that a given example configuration of the air cleaning device 50 should in no way be construed as limiting the scope of the present invention.

Although not specifically shown in these example embodiments, the air purification apparatus 50 may include at least a portion of the air purification monitoring system 10 and/or the sensor device 20. For example, the air purification apparatus 50 may comprise an air purification monitoring system 10 according to any of the described embodiments, the air purification monitoring system 10 being communicatively coupled to a separate sensor device 20 according to any of the described embodiments, the air purification apparatus 50 may comprise both the air purification monitoring system 10 according to any of the described embodiments and the sensor device 20 according to any of the described embodiments.

Alternatively, the air purification apparatus 50 may comprise a wired or wireless communication module (not shown) adapted to communicate with the air purification monitoring system 10 according to any of the described embodiments, which may itself be communicatively coupled to a separate sensor device 20 according to any of the described embodiments. In this case, the air cleaning device 50 further comprises a controller arrangement (not shown) of one or more

air displacement devices

67, 69, which controller arrangement controls the one or more

air displacement devices

67, 69 in dependence of control signals generated by the processor 31 as will be explained in more detail below. In the context of the present application, such control signals may comprise one or more control instructions for the air cleaning device 50. Such control instructions configure the air purification apparatus 50 to operate in a particular mode and, as such, may instruct the air purification apparatus 50 to operate any of the

air displacement devices

67, 69, valve device 65 (if present), etc., in accordance with the configuration information conveyed by the control signals. The processor 31 is adapted to implement a method 100 according to an embodiment of the invention, a flow chart of which method 100 is depicted in fig. 7. The method 100 starts in operation 101, in operation 101 the processor 31 is activated, after which the method continues to operation 103, in which operation 103 the processor receives an indication of a spontaneous ventilation rate between the enclosed space and the outdoor space, from which indication the processor 31 determines a spontaneous ventilation rate in operation 105. As will now be explained in more detail, this is preferably based on both the received indication and an estimate of the volume of the enclosed space 1.

With respect to determining the volume of the enclosed space 1, in a simple embodiment, the volume may be specified by a user using any user interface communicatively coupled to the processor 31. This therefore relies on the user providing an accurate estimate of the volume of the enclosed space 1 to ensure that the air cleaning device 50 can operate in an efficient manner.

In an alternative embodiment, the volume of the enclosed space 1 may be estimated based on sensor information provided by the sensor device 20. In particular, the room volume may be derived from the monitored indoor particle (contaminant) concentration, for example with an analyte sensor 21, which analyte sensor 21 follows equation 1 based on the law of mass conservation:

in this formula:

c represents the concentration of particles in the room in g/m³；

P_pRepresents the permeability coefficient of particles entering the air-filled space containing the air cleaning device 50 from the outside, which in a typical household dwelling is typically about 0.8;

C_outrepresents the outdoor particle concentration in g/m³The outdoor particle concentration may be obtained as explained in the present application;

k₀denotes the natural settling rate of the particles in h^-1And is usually about 0.2h^-1；

k_vExpressing the rate of ventilation in units of h^-1；

v denotes the room volume in m³；

CADR denotes the clean air delivery rate in m³/h。

The analyte sensor 21 may record a typical CADR curve, which may be represented, for example, using a linear scale on the y-axis of a plot depicting the CADR curve. The recorded CADR curve can be represented by equation (2):

C＝m*e^-kt(2)

thus, k is the exponential decay constant with respect to the concentration curve.

By combining equations (1) and (2), the following equation (3) is obtained:

by substituting-km e^-ktEquation (4) can be obtained as follows:

initial CADR can be used to calculate the room volume V₀I.e. the volume V of the closed space 1 accommodating the air cleaning device 50. This room volume can be obtained, for example, when the air cleaning device 50 is first operated in the enclosed space 1. Instead, other suitable ways of obtaining the room volume may be applied.

In a first set of embodiments, the indication of the spontaneous ventilation rate as received by the processor 31 comprises information about outdoor wind speed, which may be received by the processor 31 from a meteorological service providing wind speed information for a geographical location of the enclosed space 1 as previously mentioned or from an anemometer (e.g. external sensor 24) located at that geographical location, for example attached to an anemometer comprising a dwelling of the enclosed space.

It is known per se that there is a relationship between the outdoor wind speed and the spontaneous ventilation rate between the enclosed space 1 communicating with the outside. This relationship is schematically depicted in fig. 8, fig. 8 depicting a rate (in h) showing the displacement (display) of the volume of the enclosure 1 according to the outdoor wind speed (in m/s)^-1In units). The graph clearly depicts: as the outdoor wind speed increases, the rate at which spontaneous ventilation between the enclosed space 1 and the outdoor space occurs also increases, so that the spontaneous ventilation rate of the enclosed space 1 can be estimated from the indicated outdoor wind speed.

In a second set of embodiments, such an indication comprises a series of sensor readings of the concentration of the analyte of interest within the enclosed space 1 over a defined period of time, wherein the processor 31 is arranged to calculate the spontaneous ventilation rate from the series of sensor readings. For example, the processor 31 may be adapted to: based on CO in the enclosed space 1 accommodating the air cleaning device 50 when one or more persons are present in the air-filled space and the air cleaning device 50 is switched off₂The natural draft rate Q is estimated as a change in concentration or any other suitable gaseous compound, such as a Volatile Organic Compound (VOC). In particular, when these people exhale CO₂C in a space filled with airO₂Should increase according to the number of people in the air-filled space and the volume of the space. Increased deviation from this expectation (i.e., CO over time)₂An increase in level that is less than expected) may be due to ventilation between the air-filled space and the outside. For example, the processor 31 may be adapted to estimate the ventilation rate Q according to equation (5):

in equation (5), croom (t) is CO in the air-filled space at a time point t, that is, a time period Δ t (in hours) after the start of the monitoring period when t is 0₂Concentration (in g/m)³As a unit), C_outdoorIs ambient CO in an environment ventilated with an air-filled space₂Concentration (in g/m)³In units) and S is CO in an air-filled space₂Source intensity (in g/m)³In units). Individual (S)_i) CO of₂The source intensity is typically in a given range (e.g., in the range of 0.16l/min to 0.33l/min for adults).

The processor 31 may calculate the source intensity S based on the determined number N of individuals in the air-filled space, e.g., S-N S_i. The number N of individuals within the air-filled space may be determined in any suitable manner, for example, the number N may be specified by a user through a user interface of the air monitoring system 10, or alternatively, the air purification monitoring system 10 may include one or more sensors (not shown) (e.g., motion detection sensors, etc.) for detecting the presence of individuals within the air-filled space. FIGS. 9 and 10 respectively depict a plurality of graphs, including CO as a function of time₂Source intensity S (upper left), Natural Ventilation Rate Q (upper right) and CO₂Graph of concentration croom (t) (lower left). In fig. 9, the enclosure 1 exhibits a low wind velocity, as evidenced by the high fluctuations in the natural ventilation rate Q due to changes in environmental conditions (such as wind conditions), while in fig. 10, the enclosure 1 exhibits a high wind velocityAnd (4) rate. This results in CO in the enclosed space 1₂The accumulations have significant differences which can be used to estimate the spontaneous (natural) ventilation rate between the enclosed space 1 and the outdoor space.

Based on secondary CO₂From a series of sensor signals received by the sensor 21, the processor 31 can determine the natural ventilation rate Q between the enclosed space 1 accommodating the air cleaning device 50 and the outside, since the CO in the air-filled space, as already explained in more detail above by means of equation (5), is present in the air-filled space₂The trend of the concentration may be used to determine the spontaneous ventilation rate Q, i.e., the ventilation rate when the air cleaning device 50 is turned off. It should be understood that equation (5) is provided by way of non-limiting example only, and may also be used, and may be based on CO₂To derive other equations for the ventilation rate Q.

The processor 31 may obtain the ambient CO₂Concentration to determine the ventilation rate Q in any suitable manner, e.g. by another CO placed in the environment₂Sensors or through a service on a network, such as the internet, that provides information about the CO in the area of interest, including the area in which the enclosure 1 is located₂(real-time) information of concentration. Processor 31 may obtain ambient CO at any suitable point in time₂And (4) concentration.

Alternatively, the natural draft rate Q may be determined by monitoring other gaseous compounds (e.g., volatile organic compounds) produced by a person within the air-filled space. Furthermore, it should be understood that the source intensity S need not be limited to the production of CO by persons within the enclosed space 1₂. For example, it is also possible: the source intensity S represents the rate at which another undesirable substance is released, such as a volatile organic compound, within the newly installed enclosed space 1. Alternatively, the spontaneous ventilation rate of the enclosed room 1 may be estimated in any other suitable manner, such as a user-specified estimate provided through a user interface in communication with the processor 31.

Of course, further improvements can be made to estimates of room volume and spontaneous ventilation rate. For example, processor 31 may be derived from analyte sensor 21(s)Such as CO₂Sensor or VOC sensor) receives a series of sensor readings, for example, to monitor CO within the enclosed space 1₂A change in level as such a change may indicate a change in volume of the enclosed space (e.g. opened or closed by a door or the like between the enclosed space 1 and an adjacent space) or a change in ventilation conditions between the air-filled space and the outside. By adverse substance levels and/or CO₂Sudden changes in the level (or levels of other contaminants monitored to determine the occupancy of the enclosed space 1 as previously explained) may detect changes in the volume of the air-filled space or changes in ventilation conditions. For example, adverse species concentrations and CO are detected at processor 31₂In case of a sudden change in concentration, the change may indicate a change in the volume of the enclosed space 1 or a change in the ventilation conditions of the enclosed space 1.

The processor 31 may distinguish between volume changes and ventilation condition changes in the following manner. Contaminants and CO being monitored in the enclosed space 1₂In the case of a volume change following an initial sudden change in level, these levels will gradually decrease until equilibrium is reached between the two connected spaces. In this scenario, CO₂Typical ambient CO levels typically remain above about 400ppm₂And (4) horizontal. CO in air-filled spaces in case of varying ventilation conditions₂The level will be rapidly in contact with the ambient CO₂Horizontal equilibrium, i.e., a level of about 400ppm is reached. In a third set of embodiments the indication of the spontaneous ventilation rate of the enclosed space 1 comprises temperature information comprising an outdoor air temperature and an indoor air temperature, wherein the processor 31 is arranged to calculate the spontaneous ventilation rate from the difference between the outdoor air temperature and the indoor air temperature. The indoor temperature (i.e., the temperature within the enclosed space 1) may be determined using the temperature sensor 22, and the outdoor temperature may be determined using the outdoor temperature sensor 24, or alternatively, the outdoor temperature may be provided by an external source, such as a weather service as explained previously. Fig. 11 schematically depicts a rate (in h) showing the complete filling of the volume of the enclosed space 1 by spontaneous ventilation^-1In units) andgraph of the relationship between the temperature difference (in c) between the outdoor and indoor temperatures. From this graph, it can be seen that: an indication of the spontaneous ventilation rate of the enclosed space 1 can be obtained from the temperature difference between these indoor and outdoor temperatures.

After determining the spontaneous ventilation rate, the method 100 continues to operation 107, where the processor 31 generates control signals for the airflow shifting device in accordance with the determined spontaneous ventilation rate in operation 107. The control signal causes the

airflow shifting device

65, 67 and/or 69 of the air cleaning device 50 to control the rate of the forced draft airflow 82 such that the forced draft airflow rate exceeds the spontaneous draft rate. In this way, spontaneous ventilation of the outdoor air into the enclosed space 1 is effectively suppressed so that the outdoor air enters the enclosed space 1 mainly by forced ventilation caused by the air cleaning device 50, which ensures that the filter device 62 inside the air cleaning device 50 removes a large amount of undesired substances in the outdoor air from the outdoor air, which passes through the filter device 62 before being released into the enclosed space 1. After the air purification monitoring system 10 generates the control signal and provides the control signal to the air purification apparatus 50, the method 100 terminates in operation 109.

Of course, further modifications may be made to the method 100. For example, the method 100 may be invoked only when the outdoor concentration of a particular type of adverse substance has exceeded a defined threshold above which the concentration of the adverse substance may be considered potentially harmful. The outdoor concentration of the adverse substance of interest may be obtained in any suitable manner, for example using an outdoor analyte sensor or an external service that provides real-time information about such concentration within the geographic location of the enclosed space 1.

As a further refinement, the processor 31 may be responsive to a pressure sensor 23 which monitors the pressure within the enclosed space 1. For example, based on the determined spontaneous ventilation rate for the enclosed space 1, the processor 31 may calculate a target pressure to be generated within the enclosed space 1 with the air purification device 50 in the forced ventilation mode as explained previously. The pressure sensor 23 may be used as a feedback mechanism to determine whether the air cleaning device 50 is operating correctly, and more specifically whether the forced draft rate is causing the desired pressure within the enclosed space 1. If the processor 31 determines from the sensor readings provided by the pressure sensor 23 that the actual pressure within the enclosed space 1 deviates from the target pressure, the processor 31 may generate another control signal for the air cleaning device 50 to adjust the forced air rate generated with the air cleaning device 50 to reduce the deviation of the actual pressure within the enclosed space 1 from the desired pressure. In this way, for example, an unnecessarily high overpressure in the enclosed space 1 can be avoided. In other words, this pressure feedback ensures that the air cleaning device 50 is operated as efficiently as possible.

The above-described embodiments of the method 100 performed by the processor 31 may be implemented by computer-readable program instructions embodied on a computer-readable storage medium, which, when executed on the processor 31, cause the processor arrangement 31 to implement the method 100. Any suitable computer readable storage medium may be used for this purpose, such as, for example, optically readable media (such as a CD, DVD, or blu-ray disc), magnetically readable media (such as a hard disk), electronic data storage (such as a memory stick, etc.), and so forth. The computer readable storage medium may be a medium accessible over a network, such as the internet, so that the computer readable program instructions may be accessed over the network. For example, the computer-readable storage medium may be a network-connected storage device, a storage area network, cloud storage, or the like. The computer readable storage medium may be an internet-accessible service from which the computer readable program instructions may be obtained. In an embodiment, the processor 31 is adapted to retrieve computer readable program instructions from such a computer readable storage medium and to create a new computer readable storage medium by storing the retrieved computer readable program instructions in the data storage device 33.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. An air purification monitoring system (10) for monitoring an air purification device (50) adapted to purify air in an enclosed space (1), the air purification device (50) comprising:

a first inlet (57) for receiving outdoor air from an outdoor space and at least one outlet (53) coupled to the first inlet (57);

a filter device (61, 63) positioned between the first inlet (55) and the at least one outlet (53); and

-airflow displacement means (65, 67, 69) arranged to generate a forced ventilation airflow (82) from the first inlet (57) to the at least one outlet (53);

the air purification monitoring system (10) comprises a processor (31) arranged to:

-receiving an indication of a rate of spontaneous ventilation between the enclosed space (1) and the outdoor space;

determining the spontaneous ventilation rate from the received indication; and is

Generating a control signal for the airflow shifting device (65, 67, 69) from the calculated spontaneous ventilation rate, the control signal causing the airflow shifting device (65, 67, 69) to control the rate of the forced ventilation airflow (82) such that the forced ventilation airflow rate exceeds the spontaneous ventilation rate.

2. The air purification monitoring system (10) according to claim 1, wherein the processor (31) is arranged to determine the spontaneous ventilation rate based on the indication and a volume of the enclosed space (1).

3. The air purification monitoring system (10) according to claim 1, wherein the indication comprises a series of sensor readings of the concentration of the analyte of interest within the enclosed space (1) over time, and wherein the processor (31) is arranged to calculate the spontaneous ventilation rate from the series of sensor readings.

4. The air purification monitoring system (10) according to claim 3, further comprising an analyte sensor (21) arranged to provide the series of sensor readings.

5. The air purification monitoring system (10) according to claim 1, wherein the indication comprises outdoor wind speed information.

6. The air purification monitoring system (10) according to claim 1, wherein the indication comprises an outdoor air temperature and an indoor air temperature, and wherein the processor (31) is arranged to calculate the spontaneous ventilation rate from a difference between the outdoor air temperature and the indoor air temperature.

7. The air purification monitoring system (10) of claim 6, further comprising at least one of: an indoor temperature sensor (22) for determining the indoor air temperature; and an outdoor temperature sensor (24) for determining the outdoor air temperature.

8. The air purification monitoring system (10) according to claim 1, wherein the processor (31) is further arranged to:

receiving pressure sensor readings from a pressure sensor (23) indicative of a pressure within the enclosed space (1); and is

Generating the control signal for the airflow displacement device (65, 67, 69) in dependence on the spontaneous ventilation rate and the pressure sensor reading.

9. The air purification monitoring system (10) according to claim 8, further comprising the pressure sensor (23).

10. An air purification device (50) adapted to purify air in an enclosed space (1), comprising:

a filter arrangement (61, 63) positioned between the first inlet (57) and the at least one outlet (53); and

-an airflow shifting device (65, 67, 69) arranged to produce a forced ventilation airflow (82) from the first inlet (57) to the at least one outlet (53), wherein the airflow shifting device (65, 67, 69) is responsive to the control signal generated with the air purification monitoring system (10) as claimed in claim 1.

11. The air purification device (50) of claim 10, further comprising: the air purification monitoring system (10) according to claim 1.

12. The air purification apparatus of claim 10, further comprising a second inlet (55) for receiving indoor air from the enclosed space, the enclosed space being coupled to the at least one outlet (53), and wherein:

the filter device (61, 63) is positioned between the first and second inlets (57, 55) and the at least one outlet (53); and

the gas flow shifting means (65, 67, 69) is further arranged to generate a recirculating gas flow (81) from the second inlet (55) to the at least one outlet (53).

13. A computer-implemented method (100) for generating a control signal for controlling an air purification device (50) according to any one of claims 10 to 12, the method (100) comprising:

-receiving (103) an indication of a spontaneous ventilation rate between the enclosed space (1) and the outdoor space;

determining (105) the spontaneous ventilation rate from the received indication; and generating (107) a control signal for the airflow shifting device (65, 67, 69) in dependence on the calculated spontaneous ventilation rate, the control signal causing the airflow shifting device (65, 67, 69) to control the rate of the forced ventilation airflow (82) such that the forced ventilation airflow rate exceeds the spontaneous ventilation rate.

14. The computer-implemented method (100) of claim 13, wherein determining (105) the spontaneous ventilation rate from the received indication comprises: determining the spontaneous ventilation rate based on the indication and the volume of the enclosed space (1).

15. A computer program product comprising a computer readable storage medium having computer readable program instructions for causing a processor (31) of an air purification monitoring system (10) as defined in any one of claims 1 to 9 to carry out the method (100) as defined in claim 13 or 14 when executed on the processor (31).